This invention relates to coffee makers for centrifugally brewing coffee by rotating a brewing case containing milled coffee beans at high speed by a motor with hot water simultaneously fed to the brewing case from a hot water feed mechanism.
Coffee makers of the type described above are suitable for preparing "espresso"-like coffee and disclosed in Japanese Laid-open Utility Model Application No. 63-37142 and German Patent No. DE 3137651 A1. A brewing case for containing milled coffee beans is provided above an electric motor and a small space is defined between the upper peripheral edge of the brewing case and a lid closing the upper open end of the brewing case. The brewing case is rotated at high speed by the motor so that a centrifugal force due to rotation causes hot water to quickly pass through the milled coffee beans and then through the small space between the case and the lid, thereby making coffee. This coffee brewing manner is advantageous in that coffee is quickly made. Further, since a period during which the hot water is in contact with the milled coffee beans is relatively short, ingredients degrading flavor of coffee such as the ingredient of bitterness are not extracted from the milled coffee beans, thereby improving the flavor of coffee.
In the coffee maker disclosed in Japanese Laid-open Utility Model Application No. 63-37142, a heating case is provided below the brewing case for heating the water therein. A hot water feed tube is extended downwardly from the central bottom of the brewing case to the interior of the heating case. After the hot water is made in the heating case, the brewing case and the hot water feed tube are together rotated at high speed, whereby the hot water in the heating case is sucked to the brewing case through the hot water feed tube. Consequently, the hot water supply to the brewing case necessarily starts after the start of rotation of the brewing case. When the hot water supply starts after the start of rotation of the brewing case, a centrifugal force acts on the hot water supplied to the brewing case rotating at high speed from the first of the hot water feed and consequently, the hot water is caused to splash around ununiformly. Accordingly, at the first of the hot water supply to the brewing case, some part of the milled coffee beans in the brewing case includes hot water and some does not, which unbalances the brewing case. When the brewing case is rotated at high speed in the unbalanced state, the case is caused to intensely oscillate, producing a big noise.
The coffee maker disclosed in the above-mentioned German Patent is not provided with a hot water feed mechanism and accordingly, a user needs to supply hot water with a kettle or the like. Therefore, a lot of time is needed for the making of coffee and the usability is reduced.